Somerset County leans Democratic by roughly 16 points: about 58% of voters vote Democratic and 42% Republican.
About 77% of adults in Somerset County typically vote, above the U.S. average of about 62%. Among adults in Somerset County, ~45% vote Democratic, ~32% Republican, and ~23% don't vote. The map below shows estimated turnout by block group.
How Somerset County compares
Among counties within 50 miles, Somerset County leans more Democratic than 14 of 25 neighbors.
Somerset County runs about 10 points more Democratic than New Jersey as a whole.
Politics vary noticeably by city within Somerset County. The southeast side is the most Democratic-leaning (D+43) and the northwest side is the least Democratic-leaning (D+3), a spread of about 40 points.
Why Somerset County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Somerset County, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 58% of adults in Somerset County hold a bachelor's degree, about 29 points above the U.S. average of 28%. Dense areas vote Democratic, and Somerset County sits in the top fifth on density (about 71%, above 91% of counties).
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Somerset County, NJ sits in the top tenth nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Somerset County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Somerset County is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 70%, about 10 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 94% of adults in Somerset County have completed high school, above 84% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Middlesex County, NJ D+11
- Union County, NJ D+26
- Hunterdon County, NJ R+6
- Morris County, NJ Even
- Mercer County, NJ D+38
- Richmond County, NY R+21
- Essex County, NJ D+48
- Warren County, NJ R+16
- Monmouth County, NJ R+8
- Hudson County, NJ D+27
Counties with Similar Populations
- Marion County, OR D+3
- Hamilton County, IN R+5
- Rutherford County, TN R+16
- Galveston County, TX R+13
- Horry County, SC R+30
- Rockland County, NY R+14
- Nueces County, TX R+4
- Westmoreland County, PA R+26
- Cumberland County, NC D+20
- Henrico County, VA D+31
Sources and methodology
Precinct-level voting records used to fit the model come from New Jersey Division of Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.
Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.
Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.